Scientific Programme

Bladder cancer (BC) progression is driven by molecular heterogeneity and interactions in the tumor microenvironment that remain incompletely understood. To investigate the molecular drivers of BC progression we profiled BC patients’ biopsies and identified a 16-genes program of progression/recurrence where PDGFRβ (Platelet-Derived Growth Factor Receptor Beta) is acting as a central node. To define its tumor-cell intrinsic role, we combined spatial proteo-transcriptomic profiling of human BC biopsies with in vitro functional analyses and in vivo therapeutic targeting using orthotopic mouse models.

High PDGFRβ expression at both the transcript and protein levels correlated with increased disease aggressiveness and poor patient survival. Functionally, PDGFRβ promoted cancer cell invasion and regulated transcriptional programs associated with cell migration. Mechanistically, macrophage-derived Galectin-9 induced PDGFRβ expression through a tumor-cell intrinsic CD40-dependent axis.

In vivo, CRISPR/Cas9 mediated PDGFRβ deletion in cancer cells reduced tumor growth and metastasis and reshaped the immune microenvironment toward an immune-hot milieu, characterized by increased infiltrations of CD8⁺ T cells, B cells, and anti-tumoral macrophages. More importantly, pharmacological inhibition using the selective PDGFRβ inhibitor CP-673451 improved survival in orthotopic models.

Our data shows that tumor cell–intrinsic PDGFRβ drives BC aggressiveness by integrating invasive transcriptional programs with immune modulation and thereby reveal a molecular target for therapy of advanced BC.

The development of chimeric antigen receptor T-cell (CAR-T) therapies has emerged as a transformative approach for the treatment of hematological malignancies and holds promise across diverse cancer types. However, progress remains constrained by key challenges, including limited infiltration into the tumour microenvironment, treatment-associated toxicities, and poor persistence of effector function driven by T-cell exhaustion resulting from persistent antigen exposure or intrinsic tonic signaling. In addition, preclinical development of novel CAR-T strategies is hindered by poor translatability between animal models and clinical outcomes.

This translational gap has driven the emergence of new approach methodologies (NAMs), encompassing in vitro systems such as microfluidic platforms, organoids, and 3D culture models. In this project, we aim to develop a NAMs-based platform to visualize and characterize T-cell motility and tumour cell interaction dynamics under baseline and experimental conditions, including exposure to immunotherapeutic agents. The 3D co-culture system will enable acquisition of morphological, migratory, and interaction data via time-lapse fluorescence microscopy, with bespoke computational tools applied to quantify and classify T-cell behaviours. To validate the in vitro model, intravital microscopy will provide a physiological reference for T-cell behaviour in vivo. Collectively, this approach aims to establish a predictive platform for evaluating CAR-T cell function and supporting the development of more effective immunotherapeutic strategies.

Introduction and Aim of the study

Colorectal cancer (CRC) is the second-leading cause of cancer deaths worldwide. During carcinogenesis, alteration of the gut epithelial barrier allows the translocation of gut bacteria to the tumor tissue and their interaction with immune cells. Infiltration by T cells is associated with improved survival, but their interplay with gut bacteria has not been fully investigated. We previously identified a panel of bacteria whose abundance in CRC tissues correlates with T cell infiltration. In this work, we investigated the capacity of these bacteria to induce T cell-mediated anti-tumor responses.

Design and Methods

Peripheral blood mononuclear cells from healthy donors or CRC patients were cultured with gut bacteria of interest and assessed for proliferation based on CFSE dilution. Phenotypes and functionality of proliferating T cells were assessed by FACS. CRC and adjacent normal tissue biopsies were processed to obtain single-cell suspensions. Phenotypes and signatures of tumor-infiltrating T cells were assessed by FACS and single-cell RNA-sequencing.

Results and Conclusions

Proliferating cells to bacteria mostly consisted of CD4-CD8- double negative T cells expressing Vδ2+ γδTCRs. Expanded Vδ2+ γδT cells formed immunological synapses and showed BTN3A1-independent tumor cell killing. Tumor-infiltrating Vδ2+ γδT cells are detected within CRC tissues, and their transcriptomes partially overlapped with those expanded upon bacterial stimulation from peripheral blood. Their anti-tumor potential is currently under evaluation.

T cell exhaustion is a state of T cell dysfunction, characterized by reduced proliferation capacity, cytokine production, and loss of responsiveness to immune checkpoint blockade. Growing evidence demonstrates that global epigenetic alterations are the critical events to drive T cell exhaustion under persistent antigen exposure. However, it is unclear how the epigenetic alteration is established in an irreversible manner. In murine melanoma model, we found depolarized mitochondria accumulated in tumor-infiltrating CD8+ T cells (TILs), which exhibited more severe exhausted phenotype such as reduced cytokine production and upregulation of co-inhibitory receptors, suggesting metabolic stress in tumors can drive T cell exhaustion. Further analyses revealed that the genes involved in DNA damage response (DDR) were enriched in the TILs with depolarized mitochondria. We further found that TILs accumulated dysfunctional mitochondria and acquired γ-H2AX, a marker of DNA break, expression in tumors over time. Intriguingly, DNA damage enhanced exhausted phenotype, manifesting by increased PD-1, TIM-3, and TOX while decreased IFN-γ and TNF-α expression, and the phenotype was sustained even when DNA damage was resolved. Most importantly, we found global epigenetic alterations with enhanced T cell exhaustion landscape upon DNA damage. CRISPR screen targeting DDR pathway identified a critical role of histone acetylation in DDR-driven T cell exhaustion. Together, our study reveals that mitochondrial fitness and DNA damage signaling may determine the fate of T cell toward exhaustion.

CD8+ T cell exhaustion is a major barrier to effective cancer immunotherapy. This dysfunctional state is reinforced by a fixed epigenetic program. Checkpoint inhibitors (e.g. aPD-1) efficiently reinvigorate exhausted CD8+ T cells (T_ex) but ultimately fails at epigenetically reprogramming these cells. Complementary strategies are therefore needed to address this limitation and improve therapy outcomes. Recent studies showed that the g_c-cytokine IL-2 partially reverses the epigenetic program of exhaustion and synergize with PD-1 blockade. Our preliminary data identifiy IL-4 as an alternative yc cytokine with enhanced capacity to expand Tex cells and reduce exhaustion features. Using the LCMV mouse model, we investigated the physiological impact of IL-4 on Tex differentiation and its interaction with PD-1-based therapy. We uncovered a predominant expression of the IL-4 receptor a-chain (IL4Ra) and constitutive STAT6 activation in progenitor exhausted T cells (Tex^prog), the subset most responsive to PD-1 blockade. Functional studies combining IL-4 blockade and Stat6 genetic knock-down reveal that the IL-4/Stat6 axis regulates the transition from Tex^prog to intermediate Tex (Tex^int) – an effector-like population mediating therapeutic responses - in both chronic LCMV infection and tumor models. In human and murin in vitro systems modelling exhaustion, we confirmed the tremendous ability of IL-4 at expanding Tex cells and reinforcing the cytotoxic program in these cells. Together, these findings highlight IL-4 as a powerful combinatorial agent to PD-1-based immunotherapies. 

T cell exhaustion is a hypofunctional state characterized by impaired effector function and proliferation, ultimately limiting antitumor efficacy. We recently uncovered that tumor infiltrating lymphocytes (TILs) accumulate damaged mitochondria, which is sufficient to drive functional and epigenetic reprogramming leading to T cell exhaustion. To identify molecular targets for sustaining mitochondrial fitness in TILs, by performing an in vivo CRISPR-Cas9 screen of over 700 murine kinases. Among the guide RNA hits that enhanced mitochondrial fitness, we identified the cell-cycle regulator cyclin-dependent kinase 4 (CDK4). Notably, CDK4/6 inhibitors have been reported to promote CD8⁺ T cell activation and memory formation, with mechanisms that remain unclear. In our screen, CDK4-deficient T cells were enriched within the population with high mitochondrial fitness, whereas CDK6-deficient cells were not, suggesting a CDK4-specific role. Using both in vitro chronic stimulation of human T cells and murine tumor models, we show that T cell-specific CDK4 knockout (KO) preserves mitochondrial integrity and effector function in the tumor microenvironment, resulting in improved tumor control. CDK4 KO leads to upregulation of PGC1a and transcriptional changes indicative of increased mitochondrial metabolism. In contrast, although CDK6 depletion enhanced cytokine production, it did not affect mitochondrial fitness or tumor progression. Collectively, these findings uncover a previously unrecognized role for CDK4 and highlight its potential as a target to enhance T cell–based therapies.

T cells able to infiltrate the tumor can reach a state of “exhaustion”, characterized by reduced functionality and the expression of inhibitory receptors, such as PD-1. Blocking antibodies against this receptor are currently used in clinics, but the signalling and the signature downstream of PD-1 remains an open question.

To study the tumor response and to identify potential targets involved in PD-1 signalling cascade, we generated mice lacking PD-1 in the T cells. These mice showed a slower tumor growth and an increased infiltration of CD8⁺ T cells, in particular of T exhausted cells. ScRNA-sequencing on immune infiltrates identified pathways upregulated in absence of PD-1, allowing us to select candidates to be tested by genetic approches for their relation to the downstream mechanism of PD-1.

Our results will help gain insights into the role of PD-1 in shaping the anticancer CD8⁺ T cell responses and pinpoint new targets for therapies.

Kupffer cells (KCs) are liver-resident macrophages that maintain hepatic homeostasis, but their contribution in anti-tumor immunity against hepatocellular carcinoma (HCC) remains unclear. Here, we uncover that KCs are bona fide antigen-presenting cells (APCs) capable of acquiring tumor antigens and priming CD8 T cells. Compared with dendritic cells, KC-mediated priming drives a distinct trajectory coupling polyfunctional effector activity with memory-like features. Integrated single-cell transcriptomics and interactome analysis reveals a KC-specialized CD169-CD43 co-stimulatory axis that isnecessary and sufficient for this program, which monocyte-derived KCs (MoKCs) progressively acquire. Depletion studies further demonstrate that combined loss of KCs and MoKCs diminishes tumor-reactive CD8 T cells, thereby accelerates HCC progression. In human HCC, co-expression of CD169 and CD43 correlates with a KC-primed CD8 T cell signature and associates with improved survival. These findings redefine intrahepatic priming and uncover the CD169-CD43 signaling as a potential target for therapeutic engineering of durable antitumor CD8 T cells.

Despite growing interest in Natural killer (NK) cell-targeting immunotherapies for cancer treatment, the differentiation and functional states of tumor-infiltrating NK cells remain poorly understood. Using matched single-nucleus RNA and ATAC sequencing of non-small cell lung cancer (NSCLC) specimens, we resolved the transcriptional and epigenetic landscape of intratumoral NK cells. We identified two tumor-associated NK (taNK) cell subsets marked by ITGAE (CD103) and ITGA1 (CD49a) that display features of tissue residency and dysfunction while preserving cytotoxic function. Trajectory and regulon analyses revealed an inflammation-driven transition from early GZMK⁺ NKs toward an ENTPD1⁺ (CD39⁺) effector state characterized by interferon-stimulated gene (ISG) programs. Functional profiling established CD39⁺ taNK as the dominant cytotoxic NK cell population with superior killing capacity that is further potentiated by NKG2A blockade. This study offers mechanistic insights into NK cell differentiation in NSCLC and establishes CD39⁺ taNK cells as a targetable effector population for immunotherapy.

Introduction and aim of the study:
mRNA technology has been pivotal for anti-SARS-CoV-2 vaccine development and is being explored for other infectious diseases. However, mRNA vaccines may induce variable and short-lived antibody responses. Since gut microbiota influences host immunity, we investigated its role in responsiveness to the BNT162b2 vaccine.

Design and methods:
Gut microbiota impact on vaccine responsiveness was evaluated in murine models and in COVID-19-naïve healthy donors vaccinated with BNT162b2 (n=121). Associations between bacterial taxa and antibody titers were analyzed. To assess causality, fecal microbiota transplantation (FMT) from good- and bed-responder donors was performed in naïve mice before vaccination. Mechanistic studies included metabolic pathway analysis and histone H3 acetylation assessment in germinal center B cells.

Results:
Specific bacterial taxa were associated with enhanced or impaired antibody responses in mice and humans. In vaccinated donors, antibody titers correlated with defined microbial populations. Mice receiving FMT from good responders developed stronger humoral responses than mice receiving microbiota from bad responders. Enhanced responsiveness was associated with activation of specific metabolic pathways and increased histone H3 acetylation in germinal center B cells.

Conclusions:
Gut microbiota composition influences responsiveness to BNT162b2 vaccination through metabolic and epigenetic modulation of B-cell function, identifying microbiota-derived signals as potential targets to improve mRNA vaccine efficacy.

Successful bone regeneration depends on an immune environment that balances inflammation with repair, yet conventional bone substitutes are often evaluated mainly for osteoconductivity rather than immunomodulation. We investigated the immune effects of a fibrin-based scaffold combined with calcined bovine bone particles. Human peripheral blood mononuclear cells were exposed to fibrin sealant (EVICEL), calcined bone particles, and control particles for up to 48 hours. The inflammatory secretome was analyzed by targeted proteomics using Olink inflammation and bone remodeling panels, and cellular phenotypic shifts were assessed by single-cell mass cytometry (CyTOF) at 24 and 48 hours using a 30-marker panel. Proteomic analysis revealed a regenerative shift in EVICEL and bone combinations, marked by a high OPG/TRANCE ratio that may limit bone resorption, increased VEGFA and TGF-β1, and reduced MMP-1 and MMP-10 compared with inflammatory controls. CyTOF profiling showed reduced T-cell activation, reflected by lower CD25 and CXCR3, while survival markers CD127 and CD28 were preserved. In parallel, CD14+CD16+ monocytes and CD11c+ dendritic cells were significantly sustained, coinciding with increased tissue-repair signatures including CCR4 and CXCR5 and expansion of γδ T cells. These findings show that fibrin-based matrices differentially regulate immunity to favor regeneration by suppressing nonspecific T-cell inflammation, preserving myeloid precursors, and promoting an osteogenic proteomic state characterized by high OPG/TRANCE ratios.

Immune complexes (ICs) are known to enhance immune responses. Yet pre-existing antibodies can suppress rather than boost vaccine immunity, a phenomenon known as antibody-mediated immune suppression. However, the mechanism responsible for this suppression is not fully understood. In this study we passively immunize mice with the anti-hemagglutinin (HA) monoclonal antibody H36-7, 2h before vaccination with either UV-inactivated whole influenza virus or recombinant HA alone, generating large or small ICs, respectively. Responses were assessed by ELISA, ELISPOT, flow cytometry, and confocal microscopy. Pre-immunization suppressed influenza-specific antibody responses, T cell priming, and local inflammation only with large ICs but not with HA antigen alone, despite equivalent antigen quantities reaching the draining lymph node. In addition, we observed that the inhibition of the immune response in the large ICs was selectively mediated by FcγRIIb expressed on DCs, diverting antigen toward degradation and preventing T cell activation. The suppression was abrogated in FcγRIIb-knockout mice and upon Fc deglycosylation. In conclusion, IC size acts as a molecular switch controlling immune fate through FcγRIIb. This mechanism likely extends beyond influenza — in any context where ICs form, such as autoimmune diseases or chronic infections, this axis may shape whether immunity is amplified or silenced, offering a targetable pathway to tune immune responses.

Background: Flavor additives are widely used in foods and inhalable products such as electronic cigarettes and fragrances. Maltol and ethyl maltol can reach concentrations up to 1–2%, potentially exposing the nasal epithelium to high local doses. However, their effects on epithelial barrier function remain unclear.

Methods: Primary human nasal epithelial cells were used to generate 3D nasal organoids. Cell viability, epithelial integrity, permeability, and reactive oxygen species (ROS) were assessed using MTT, FITC-dextran, and oxidative stress assays. Secreted proteins were analyzed by targeted proximity extension assay, and organoids underwent untargeted mass spectrometry.

Results: Maltol and ethyl maltol reduced cell viability at 0.03125% and 0.001%. Both impaired epithelial integrity and increased permeability at sub-use levels. They induced dose-dependent ROS, with ethyl maltol triggering rapid ROS increase within 5 min at 0.5%. Targeted proteomics showed immune modulation: maltol increased CCL20 while suppressing IL-2 and FGF-19; ethyl maltol caused broader suppression, including IL-2 and IL-10RB. Untargeted proteomics revealed that high-dose maltol increased extracellular matrix proteins (SERPINE1, PLOD2) and reduced adhesion proteins (ITGA3, ITGAV, CD109).

Conclusions: Maltol and ethyl maltol disrupt epithelial barrier integrity and induce cellular stress at sub-cytotoxic concentrations. Proteomic data indicate impaired epithelial immune and stress signaling, raising concerns about nasal epithelial health.

The NLR family Pyrin domain containing 3 (NLRP3) inflammasome is a cytosolic multi-protein immune sensor tuned to avoid assembly at steady state. In this study, we focused on neutrophils in Cryopyrin Associated Periodic Syndrome (CAPS) patients revealing heterogeneous subtypes using CyTOF analysis of patient blood samples. In Nlrp3 mutant mice, activating Nlrp3 mutations identified essential and non-redundant functions for gasdermin (GSDM) D and GSDME. Combined deletion is required to eliminate IL-1b secretion, prevent pyroptosis, and mitigate autoinflammation, as revealed using western-blot and ELISA. The absence of both GSDMD and GSDME reduces Caspase-1 cleavage and pro-IL-1b processing, while knockout of GSDMD alone increases GSDME cleavage and caspase-8 cleavage. Clusters of GSDMD and GSDME pores can be visualized at the plasma membrane of activated CAPS neutrophils using a combination of atomic-forece microscopy and high-resolution confocal microscopy. These findings suggest that the coordinated actions of membrane-associated GSDMD and GSDME reinforce cytosolic NLRP3 inflammasome activation to control IL-1 secretion, lytic cell death, and autoinflammation.

Introduction and aim of the study: The role of tumor-associated neutrophils (TANs) in colorectal cancer (CRC) remains controversial. We investigated whether intratumoral microbiota modulates TAN recruitment and antitumor activity.

Design and methods: Bacteria-induced neutrophil activation was assessed by flow cytometry using surface activation markers. TAN phenotyping was performed on freshly resected CRC and matched non-tumor tissues using large-scale flow cytometry. Clinical correlations between bacterial load, TAN density, Siglec-14 expression, and patient survival were assessed in human CRC samples.

Results: Fusobacterium nucleatum (Fn) promotes the production of neutrophil-recruiting chemokines by tumor cells and enhances neutrophil migration more efficiently than Bacteroides fragilis. Importantly, Fn, triggers neutrophils to release cytotoxic proteins showing tumoricidal activity in vitro and in xenograft models. Mechanistically, these effects are elicited upon Fn binding to sialic-acid-binding immunoglobulin-like lectin (Siglec)-14 expressed by neutrophils but are impaired upon Siglec-14 blockade or loss-of-function polymorphisms. Supporting these findings, in human CRCs, elevated Fn loads and high TAN densities correlate with improved prognosis, whereas lack of Siglec-14 expression is associated with reduced patient survival.

Conclusions: Our findings identify microbiota composition and host genetic background as critical determinants of neutrophil functional profiles, offering insights into neutrophil-targeted therapeutic strategies in CRC.

DLBCL is a clinically and biologically heterogeneous disease in which the TME shapes tumor progression and response to therapy. The LN is a primary site of tumor initiation and dissemination, yet how the spatial localization of lymphoma cells within distinct LN microanatomical compartments influences the local TME and antitumor immune response remains unclear.

In this study, we describe how the intranodal compartmentalization of DLBCL differentially modulates the antitumor immune response. Using syngeneic Eμ-myc B-cell lymphoma mouse models, we characterized two distinct TME in the cortical and medullary regions of the LN, formed following lymphatic or hematogenous dissemination of lymphoma cells, respectively. We demonstrated through cytokine screening and transcriptomics analysis that differential TME formation can determine the inflammatory environment. This influences immune cell responses and the tumor ability to spread in the lymphatic system. Mechanistically, we found that IL-1α secreted specifically by LN macrophages within the cortical TME suppresses NK cell activity. Intravital imaging revealed that cortical NK cells exhibited directed motility, whereas medullary NK cells displayed scanning and engager behaviors. Importantly, in vivo cytokine neutralization restores NK cell function, limiting lymphoma progression.

In summary, our study identifies LN microanatomical compartmentalization as a key determinant of immune evasion in DLBCL and position IL-1α as both a prognostic biomarker and a tractable therapeutic target for restoring NK cell-mediated immunosurveillance.

Introduction: Sebetralstat is the first oral therapy approved for on-demand treatment of hereditary angioedema (HAE) attacks. In alignment with HAE treatment guidelines, participants in the KONFIDENT trial were instructed to treat attacks as early as possible and to consider treating all attacks, regardless of location or severity.

Methods: In KONFIDENT, participants ≥12 years old treated ≤3 attacks with 1 or 2 doses of sebetralstat 300 mg, sebetralstat 600 mg, or placebo. Primary endpoint: time to beginning of symptom relief (PGI-C rating of at least “A Little Better” for 2 time points in a row) within 12h. Key secondary endpoints: time to reduction in severity (decrease in PGI-S for 2 time points in a row) within 12h and time to complete attack resolution (PGI-S rating of “None”) within 24h.

Results: 110 participants treated 264 attacks (87 with sebetralstat 300 mg, 93 with sebetralstat 600 mg, and 84 with placebo). Median time to treatment was 41 min (IQR, 6-140). Median time to beginning of symptom relief was significantly faster with sebetralstat 300 mg (1.61h [IQR, 0.78-7.04]; P<0.001) and 600 mg (1.79 [IQR, 1.02-3.79]; P=0.001) compared with placebo (6.72h [IQR, 1.34->12]), as was reduction in severity (P=0.0036 and P=0.0032, respectively) and complete attack resolution (P=0.0022 and P<0.0001, respectively). Sebetralstat had a safety profile comparable with placebo.

Conclusions: Results support use of sebetralstat as a safe and effective on-demand treatment, offering a preferred route of administration, facilitating early treatment, and providing rapid symptom relief.

Background: Intralymphatic immunotherapy (ILIT) has been investigated for two decades in small clinical trials, mostly using native allergens adsorbed to aluminium hydroxide (alum). This randomised, double-blind, placebo-controlled study evaluated the safety and efficacy of ILIT with a grass pollen allergoid formulated with microcrystalline tyrosine (MCT).

Methods: Sixty adults with grass pollen–induced allergic rhinoconjunctivitis (ARC) were randomised to receive ILIT with grass allergoid (60 ng Phl p 5; n=31) or placebo (n=29). Three ultrasound-guided injections (100 µl) were administered into inguinal lymph nodes at 4-week intervals in early 2022. The primary endpoint was the combined symptom and medication score (cSMS), recorded daily during the 2022 and 2023 pollen seasons. Secondary endpoints included safety, RQLQ, serology, spirometry, FeNO, and skin-prick testing (SPT). An open-label extension was conducted in 2024.

Results: ILIT was well tolerated, with no severe adverse events. Mild local reactions (wheal, erythema, swelling) occurred after 53.8% of active injections; three moderate reactions (3.2%) were reported. In the placebo group, one mild reaction occurred. No allergen-specific systemic reactions were observed. Compared with placebo, ILIT reduced cSMS by 33% in 2022 and 50% in 2023, with sustained effects. RQLQ improved by 22% and 13%, respectively.

Conclusion: ILIT with a grass pollen allergoid formulated with MCT was safe and associated with clinically relevant reductions in symptoms and medication use in grass pollen–induced ARC.

Background: Protection after a single dose of an RSV vaccine is not lifelong, and revaccination may be needed. Homologous revaccination with mRNA-1345 at 12 or 24 months induces non-inferior immune responses compared with primary vaccination, however heterologous schedules have not been previously studied. We report immunogenicity and interim safety of mRNA-1345 revaccination ≥12 months after primary vaccination with a licensed RSV protein subunit vaccine.

Methods: Adults aged ≥60 years who had received a licensed RSV protein subunit vaccine ≥12 months before enrollment received mRNA-1345. Various safety assessments were included. Immunogenicity was assessed using neutralizing antibody (nAb) against RSV-A and RSV-B at D1 and D29 post-revaccination.

Results: 507 participants were enrolled; median interval since primary vaccination was 23 months. Injection-site pain was the most common local reaction and fatigue, myalgia, and headache the most frequent systemic reactions. nAb titres increased substantially from baseline to Day 29 for both RSV-A and RSV-B. In a post-hoc comparison of D29 post-heterologous revaccination titers with D29 post-primary vaccination (mRNA-1345), the geometric mean ratios for RSV-A and RSV-B were 0.952 (95% CI, 0.847-1.070) and 1.087 (95% CI, 0.964-1.226). GMFR and seroresponse rate were consistent with those observed following homologous revaccination with mRNA-1345 in a separate study.

Conclusion: These findings support revaccination with mRNA-1345 ≥12 months after primary vaccination with an RSV protein subunit vaccine.

Encore abstract (ESCMID 2026)

Introduction and Aim of the Study

Oral immunotherapy (OIT) is a disease-modifying therapy for IgE-mediated food allergy, but real-world success is limited by treatment burden and early discontinuation. This study assessed rates, reasons and timing of OIT discontinuation in a real-world pediatric multi-allergen cohort.

Design and Methods

In this single-center observational study, pediatric patients starting OIT between July 2022 and March 2026 were enrolled. Reasons for discontinuation were recorded at cessation and by chart review, and classified as adverse events (AE) or non-AE factors (taste aversion, logistical barriers, anxiety/distress). Baseline characteristics were compared, and hierarchical clustering explored phenotypes in discontinuation cases.

Results

Among 407 OIT courses in 306 patients, 61 (15%) were discontinued. Rates were highest for milk and wheat and lowest for cashew and sesame. Taste aversion and AE were the leading reasons (41% each), followed by logistics (11%) and anxiety/distress (7%). AE-related discontinuation occurred earlier, whereas taste aversion predominated during maintenance and occurred across all age groups. Higher sIgE were associated with AE-related discontinuation. Cluster analysis identified three phenotypes; in a high-risk cluster, taste aversion was the main cause.

Conclusion

In this real-world multi-allergen cohort, OIT discontinuation was driven equally by AE and behavioral barriers. Taste aversion was a major determinant of adherence. Patient-centered strategies addressing immunological and practical barriers may improve OIT success.

Respiratory viruses including influenza A and SARS-CoV-2 cause recurrent pandemics driven by antigenic evolution and therapeutic resistance. We exploited conserved high-mannose glycans on viral surface glycoproteins as a variant-independent target, evaluating a plant-derived lectin and its humanised lectin-antibody fusion (lectibody) combining glycan-targeting specificity with IgG1 Fc-mediated effector properties.

Plant lectin binding was characterised by ELISA, enzymatic deglycosylation, and SPR. Antiviral efficacy was assessed in pseudovirus and live virus neutralisation assays. The lectibody was produced in CRISPR-engineered N. benthamiana and characterised for Fc-mediated effector functions including ADCC and complement activation. Efficacy was validated in murine influenza A and SARS-CoV-2 infection models.

The plant lectin demonstrated high-affinity binding to conserved high-mannose glycans across >15 SARS-CoV-2 variants and 3 influenza A subtypes. Neutralisation potency was retained where strain-specific monoclonal antibodies failed. Intranasal administration reduced lung viral titres and conferred protection in vivo. The lectibody format extended serum half-life, preserved broad-spectrum neutralisation, and enhanced viral clearance through Fc-mediated ADCC.

Plant lectin-Fc lectibodies exhibit potent, broad-spectrum antiviral activity by targeting conserved glycan structures essential for viral fitness. This platform represents a universal therapeutic strategy against current and emerging respiratory viruses.

Background: Oral immunotherapy (OIT) is a promising treatment for IgE-mediated food allergy, but safety concerns limit its use. Heat-denaturation of food allergens may reduce allergic reactions by lowering IgE binding. We examined how heat-induced structural changes in egg allergens affected basophil activation in egg-allergic patients.

Methods: Gal d 1 and 2 were heat-treated and analyzed for structural changes using SDS-PAGE, ELISA, NanoDSF, and circular dichroism. Peripheral blood samples were obtained from 42 patients with egg allergy. Sensitization status was determined, and basophils were isolated and incubated with native or heat-denatured egg allergen preparations. Basophil activation was assessed by leukotriene assay.

Results: Heat-denaturation caused time- and temperature-dependent structural changes in Gal d 1 and 2, resulting in reduced IgE binding. Heat-denatured allergens induced weaker basophil degranulation than native allergens, but the effect varied depending on individual IgE sensitization profiles. Among patients reacting to heat-denatured allergens, egg-white IgE levels tended to be higher, although higher doses were needed to trigger leukotriene release.

Conclusion: Heat-denaturation of egg allergens reduces IgE binding and basophil activation, although residual reactivity persists in patients with higher sensitization. Higher allergen doses were needed to trigger basophil degranulation than native allergens, indicating reduced allergenic potency. These findings support the potential of heat-denatured egg allergens as safer starting materials for OIT.

To investigate the systemic signatures of altered host-environment interactions under healthy conditions, we combined phage immunoprecipitation sequencing (PhIP-seq) profiling of serum antibody repertoires targeting 344’000 epitopes with in-depth targeted and untargeted proteomics (total 1750 proteins) in a cohort of 95 healthy adults. Our integrated analysis identified three distinct and stable inflammatory states: low, intermediate and high. When we compared healthy individuals with low-inflammatory and high inflammatory, four important protein clusters identified, including inflammation & chemotaxis, antiviral innate immunity, dendritic cell maturation and acute phase response. The high-inflammation state was characterized by an elevation of complement-pathway components (C3, C5, C9) and acute-phase reactants, was validated by higher levels of high-sensitivity C-reactive protein and was strongly enriched for a 35-protein signature associated with all-cause mortality. PhIP-Seq analysis revealed that the low- and high-inflammatory states were characterized by distinct IgG antibody repertoires, with differential reactivity against epitopes derived from Bacteroides, Clostridiales, Staphylococcus, Streptococcus and Lactobacillus. Interestingly, these responses were identified in individuals with low circulatory inflammation, suggesting high inflammation group has low anti commensal IgG immunity. These findings suggest that the “healthy baseline” is not a single uniform state but rather a range of different immune-inflammatory profiles shaped by varying mucosal exposures.

Introduction and Aim:

Peanut is a common food allergen. Oral food challenges (OFC) remain the gold standard for diagnosis and threshold determination, yet are resource-intensive and carry inherent risks. We analysed our peanut OFC cohort to compare allergic and tolerant patients and identify predictors of OFC outcomes.

Design and Methods:

We prospectively evaluated OFCs (Jul 2022 - Feb 2026) in patients naïve to oral immunotherapy, with informed consent and conclusive outcomes. For patients with multiple eligible OFCs, only the first valid was analysed.

Results:

We included 214 of 276 OFCs. Median age was 6.4 years (range 8 months – 19 years) and 43% were female. Peanut allergy was confirmed in 125 patients (median reactive dose: 300mg), while 89 were tolerant. Most allergic patients presented with oFASS-5 grade 2 (n = 50) or 3 (n = 47); 24 experienced grade 4 reactions (no grade 5). Adrenaline was required in 19 patients. In 50% of allergic patients, peanut was their sole food allergen. Allergic patients had higher median levels of peanut-specific IgE and Ara h 2. At a 0.35 kU/l cut-off, peanut-specific IgE lacked specificity, whereas Ara h 2 showed high sensitivity (88%) and specificity (85%).

Conclusion:

Ara h 2 sensitization was an accurate predictor of peanut allergy in our cohort and may support targeted allocation of clinical resources. However, OFC remains essential for threshold determination and diagnostic clarification, especially in patients with equivocal sensitization profiles.

Introduction and Aim

Immune checkpoint inhibitors (ICIs) have transformed cancer therapy but cause immune-related adverse events. Checkpoint inhibitor-induced liver injury (ChILI) is among the most common toxicities, yet its mechanisms remain poorly understood. We aimed to investigate the spatial features of ChILI at single-cell resolution in human tissues.

Design and Methods

We assembled formalin-fixed paraffin-embedded liver biopsies from cancer patients with ChILI and normal liver controls. Using multiplexed spatial proteomics, bulk TCR sequencing, RNA in situ hybridization, and spatial transcriptomics, we analyzed the immune landscape of ChILI and performed in situ T-cell clone tracking in the liver and matched tumour samples.

Results

Spatial proteomics revealed marked expansion of cytotoxic CD8+ T cells and macrophages forming spatially organized immune niches. Bulk transcriptomics demonstrated activation of interferon response pathways. TCR sequencing identified shared, hyperexpanded clones between liver biopsies and matched tumors in all analyzed patients. Spatial transcriptomics confirmed that these clonotypes exhibited a cytotoxic CD8+ phenotype in both liver and tumor tissues, localized to immune-rich niches, and engaged in CCL5-CCR1-mediated macrophage interactions.

Conclusions

This study presents a tissue-based single-cell spatial atlas of ChILI, providing direct evidence of tumour–liver T-cell clone sharing. These findings link antitumour immunity to immune-mediated liver injury and identify the CCL5-CCR1 axis as a potential therapeutic target.

Primary biliary cholangitis (PBC) is a chronic cholestatic liver disease. Reduced number, stability, and function of regulatory T cells (Tregs) in PBC limit their therapeutic use. We aimed to generate stable, functional induced Tregs (SFiTregs) from PBC-derived CD4+ T cells in vitro and compare their epigenetic profile, stability, and suppressive capacity with natural Tregs (nTregs).

CD4+ T cells were isolated from peripheral blood mononuclear cells (PBMCs) of PBC patients and stimulated using a modified protocol (Mikami et al., 2025). FoxP3, CTLA4, and Helios expression were assessed by flow cytometry and bisulfite sequencing. Function was evaluated via in vitro suppression assays. Epigenetic features, including Foxp3 gene locus for STAT5 binding, H3K27ac, and chromatin accessibility, were analyzed by Chromatin immunoprecipitation followed by sequencing (ChIP-seq) and assay for transposase-accessible Chromatin using sequencing (ATAC-seq) in nTregs, Tnaive, and SFiTregs.

Single-cell RNA-sequencing of PBMCs confirmed reduced Treg stability in PBC. The SFiTreg protocol induced DNA hypomethylation in Treg signature genes, yielding a 100-fold expansion of pure, suppressive cells. SFiTregs showed greater stability than nTregs under Th1-polarizing conditions. ATAC-seq and ChIP-seq revealed comparable baseline epigenetic profiles but differences in accessible regions.

This approach enables robust generation of functional, stable Tregs from PBC CD4+ T cells, overcoming limitations of autologous ex vivo Treg expansion and supporting their use in the PBC inflammatory liver environment.

Seladelpar (SEL) is a first-in-class delpar (selective PPAR-delta agonist) indicated for the treatment of primary biliary cholangitis (PBC), in combination with UDCA for adults with an inadequate UDCA response, or as monotherapy in UDCA-intolerant patients. We report on long-term biochemical efficacy/safety in a pooled population treated with SEL.

Pts received daily oral SEL 10mg in the ongoing, open-label ASSURE rolled over from the PBO-controlled RESPONSE or legacy SEL trials, and were pooled according to SEL initiation. Efficacy endpoints included composite biochemical response (CBR; ALP <1.67×ULN, ALP decrease ≥15% from baseline [BL], and total bilirubin ≤ULN), ALP normalization, ALP % change from BL (CfB), and other parameters through 36 months (M). Safety was assessed by exposure-adjusted AEs through 48M.

Of 337 pts, 258 were treated for ≥2yrs and 117 for ≥3yrs, 122 reached 36M as of the data cutoff (31-Jan-25). At all time points, a majority of pts achieved CBR: 69% (225/325) at 12M, 70% (181/258) at 24M, and 67% (82/122) at 36M. ALP normalized in 35% of pts (114/325) at 12M, 37% (96/258) at 24M, and 34% (41/122) at 36M. Sustained reductions in ALP observed with mean CfB: −43% at 12M, −43% at 24M, and −40% at 36M; sustained reductions also observed in ALT and GGT through 36M. SEL was well tolerated, with overall AEs reported in 83.2 pts per 100 pt-yrs in yr1 and 62.3 in yr4.

SEL led to sustained reductions in biochemical markers of cholestasis through 36M of open-label treatment. SEL was also safe and well tolerated with no new safety signals through 48M of follow-up. 

Primary biliary cholangitis (PBC) is a chronic immune-mediated cholestatic liver disease. We previously showed that microRNA-506 (miR-506) is upregulated in PBC cholangiocytes, targeting AE2 and disrupting intracellular pH, leading to PBC-like features and immune activation. Mitophagy, a pH-dependent process that removes dysfunctional mitochondria, remains unexplored in PBC. We aimed to characterize the role of mitochondrial dynamics and auto(mito)phagy in disease pathogenesis.
Single cell RNA-sequencing data from livers of PBC patients and controls, together with miR-506-overexpressing cholangiocytes (H69 miR-506) and controls were analyzed regarding mitochondrial function, auto(mito)phagy and antigen presentation.
Altered genes and proteins related to mitochondrial dynamics and auto(mito)phagy were found in PBC livers and H69 miR-506 cells, as well as increased antigen presentation and inflammation. Altered mitochondrial function, impaired mitophagy and accumulation of dysfunctional mitochondria were found in these cells. Autophagy inhibition increased cell death and antigen presentation, especially in miR-506 cells, while activation reduced bile acid-induced apoptosis. UDCA and autophagy activation improved mitochondrial function and reduced PDC-E2 overexpression.
PBC cholangiocytes show impaired mitochondrial integrity and mitophagy, promoting accumulation of dysfunctional mitochondria and abnormal antigen presentation. UDCA and autophagy activation restore these defects. Targeting mitochondrial dynamics and mitophagy may offer new therapeutic strategies for PBC.

Background & aims:
Pruritus is a frequent and burdensome symptom in chronic liver diseases, but its anatomical distribution remains poorly characterized. We used standardized body mapping to assess spatial itch patterns across liver disease etiologies.

Methods:
In this cross-sectional study, patients with pruritus completed standardized body maps indicating current and habitual itch locations. Patients were categorized into immune-mediated and cholestatic (ICLD), steatotic (SLD), and viral liver diseases (VLD). Itch severity was assessed using NRS and the 5D Itch Scale. Body maps were digitized and analyzed using automated quantitative image analysis.

Results:
Among 656 participants, 173 (26.4%) reported pruritus; complete body maps were available for 150 patients (67.7% female). ICLD represented the largest subgroup (40.7%). Mean itch intensity was 3.8±2.7 and median 5-D Itch score was 11 (IQR 8.5–15). Pruritus predominantly affected the extremities, especially volar forearms and anterior lower legs, followed by the back, while palm and sole involvement was uncommon. Current and habitual itch patterns showed high concordance. Cirrhotic patients reported less upper-body involvement than non-cirrhotic patients, while women reported itch across more body regions than men.

Conclusions:
Standardized body mapping identified a reproducible, extremity-predominant pruritus pattern across liver diseases largely independent of etiology. These findings support shared mechanisms underlying hepatobiliary pruritus and highlight body mapping as a robust tool for spatial itch phenotyping.

Natural killer T (NKT) cells are potent immunomodulatory lymphocytes implicated in the pathogenesis of autoimmune hepatitis (AIH). Upon activation by the synthetic NKT cell ligand glycolipid α-galactosylceramide (α-GalCer), NKT cells rapidly produce both IFN-γ and IL-4, cytokines with opposing roles in hepatic inflammation. The immunoproteasome (IP), a specialized proteasome variant predominant in immune cells, is known to regulate cytokine production and T cell function, yet its role in NKT cell function remains poorly understood.

Here, we investigated the effects of KZR-616 in preclinical models of inflammatory and autoimmune liver disease. We observed reduced splenic NKT cell numbers in mice deficient for IP subunits. Stimulation of mouse splenocytes with α-GalCer resulted in dose-dependent reduction of IFN-γ secretion in the presence of KZR-616, while IL-4 production increased, suggesting a functional shift toward a Th2-like cytokine profile rather than overall suppression of NKT cell activation. This effect was dependent on IL-12 signaling.

In vivo in mice, KZR-616 treatment in an α-GalCer-induced hepatitis model reduced hepatic NKT cell infiltration comparable to dexamethasone. In addition, serum alanine aminotransferase (ALT) levels were markedly decreased, indicating reduced liver injury. Ongoing studies in concanavalin A-induced and liver homogenate-induced AIH models will be presented.

Collectively, these findings demonstrate potent anti-inflammatory effects of selective IP inhibition and support the therapeutic potential of KZR-616 in autoimmune liver diseases.

Introduction: Liver transplantation (LT) is the only curative treatment for end-stage autoimmune hepatitis (AIH). We examined the evolution of LT and reLT for AIH over 35 years at a single center.

Methods: Retrospective review of 5,862 adult LTs (1990-2024). LTs for autoimmune liver disease (AILD): AIH, primary biliary cholangitis, primary sclerosing cholangitis, or overlap syndromes were included and stratified by era: pre-MELD (1990-2001), post-MELD (2002-2011), and modern (2012-2024).

Results: Among 620 LTs for AILD in 538 patients, 531 (85.6%) were primary LT (pLT) and 89 (14.4%) were reLT, with median follow up of 15 years. Of 130 patients undergoing pLT for AIH, 15 (11.5%) required 19 reLTs. Within AILD pLTs, AIH became more prevalent over time, rising from 17.7% in the pre-MELD era to 34.7% in the modern era (p<0.001). ReLT for AIH declined significantly with 11 (22.0%) pLTs in the pre-MELD era undergoing 14 reLTs, and no pLTs for AIH in the modern era undergoing reLT (p=0.001).

In the modern era, patients with AIH had a median MELD of 38 and 66.7% required ICU care prior to pLT. Despite their high acuity, 10-year patient and graft survival for AIH after pLT improved significantly between the pre-MELD and modern era, from 58.0% to 90.5% (p=0.002) and 50.0% to 88.1% (p<0.001), respectively.

Conclusions: This represents the largest single center experience with LT for AIH spanning 35 years. More accurate diagnosis of AIH in combination with advances in surgical technique and immunosuppression have led to significant improvements in long-term outcomes after LT.

Background & Aims
Primary biliary cholangitis (PBC) shows a heterogeneous clinical course. While cholestatic markers predict outcome, the role of systemic immune activation is less clear. We assessed associations between composite immune signatures and clinical outcomes in PBC.

Methods
In this retrospective cohort, inflammatory markers were grouped into composite signatures: B-cell activation (CXCL13, BAFF, APRIL), IFN-related (CXCL9, CXCL10, CXCL11), and innate inflammatory (IL-6, TNF-α, S100A9). The primary endpoint was liver transplantation or liver-related death. Cox models were adjusted for age, sex, and alkaline phosphatase (AP).

Results
Among 63 patients, 11 events occurred over a median follow-up of 4.6 years (IQR 3.5–9.8). The B-cell signature was associated with the primary endpoint in the univariable analysis (HR 1.0017, p=0.0077) and remained independently associated after adjustment (HR 1.0022, p=0.0058), corresponding to ~25% higher risk per 100-point increase. IFN-related and innate signatures were not associated with outcome. Sicca showed a trend towards an increased risk (HR 3.53, p=0.076). BAFF correlated weakly with AP (rho=0.26, p=0.043), whereas CXCL10 and CXCL13 did not.

Conclusion
A B-cell activation signature, but not IFN-related or innate signatures, is independently associated with adverse outcomes in PBC, supporting a role for B-cell–driven mechanisms in disease progression.